Oracle Database 11g Express Edition Release 18.104.22.168.0 - Production
PL/SQL Release 22.214.171.124.0 - Production
"CORE 126.96.36.199.0 Production"
TNS for 32-bit Windows: Version 188.8.131.52.0 - Production
NLSRTL Version 184.108.40.206.0 - Production
both os and database are on 32 bit windows and 11g express r2 as shown above.
impdp will not overwrite a schema during import, it can basically only do tables - if you set table_exists_action=replace as mentioned above then tables (and directly dependant objects - for example indexes) will get 'replaced' - any stored plsql code such as views/packages/procedures etc will not get overwritten - you just get errors saying the object already exists.
impdp will create the schema though (which imp never did) so it should be simple for you to just do:
drop schema xxxx;
impdp user/pass ....... (this will create the schema for you). (well it will as long as the expdp was done with enough rights - there is a bit of a funny 'feature' with this)
<moderator edit - removed link to personal blog - pl see FAQ link on top right of this page>